LINE of Duty's season six finale finally revealed the identity of "Fourth Man", H.
Much to the shock of viewers, it was revealed to be the blundering DS Ian Buckells - whose malice had been interpreted as incompetence throughout the series. Here's more about the bent copper...
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Who is Line of Duty’s Ian Buckells?
Detective Superintendent Ian Buckells is played by actor Nigel Boyle and was assigned to Hillside Lane Station Murder Investigation Team.
During series six, Buckells had been acting suspiciously, and coaxed a false testimony out of Deborah Devereux to link Terry Boyle to the murder of journalist Gail Vella.
Buckells and Devereux had been romantically involved so she was a willing witness but AC-12 soon saw through their ruse.
When Buckells was arrested, AC-12 also found an incriminating laptop hidden in his car, although he denied having any knowledge of how it got there.
Buckells was also the one who had undercover OCG member PC Ryan Pilkington (Gregory Piper) join MIU, who then went on to threaten DCI Jo Davidson.
In the final episode of season six, it was revealed that DS Buckells was in fact the man that AC-12 had been hunting down.
A key clue came in the form of his case notes from the Lawrence Christopher case, in which he spelled “definitely” as “definately”, like H had done in communication with the OCG.
It turned out that the greedy copper had been involved with the OCG since he worked on the Lawrence Christopher case in 2003. His key motive? Greed.
Hastings told him:“As you made your way up through the ranks, there wasn’t anything that you wouldn’t turn your hand to as long as the price was right,”
“That’s the top and bottom of it, isn’t it, fella?”
Buckells told AC-12: “Yeah right, I’m a blundering fool. I’m only the one who’s made total mugs out of you lot.”
When did Ian Buckells first appear in Line of Duty?
Buckells appeared in the first series of Line of Duty where he was appointed the SIO in the case of Jackie Laverty's disappearance.
This was the same series when fans were first introduced to Ryan, who supplied DCI Tony Gates with burner phones and tried to cut off Steve Arnott's fingers after he was kidnapped by the crime gang.
However, it was Buckells who decided not to take any further action against Ryan, allowing him to eventually go on to join the police force.
Buckells returned in series four when he was nominated to replace DCI Roz Huntley (Thandie Newton) on Operation Trapdoor after AC-12 tried to have her removed.
However, Kate Fleming was working undercover at the time and Buckells immediately recognised her.
Despite being asked to keep quiet, her real identity still reached Huntley, who used it to her advantage during her interview, however, Buckells claimed it wasn't him.
Is Ian Buckells ‘H’?
Technically, yes. In the series six finale, it was revealed that Buckells was an over-promoted, under-talented and incredibly greedy man.
He used his police knowledge and dodgy connections to link up all the other corrupt officers - and make millions doing so.
While living in his normal semi-detatched with his family, Buckles was a bungling detective inspector.
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But when he was acting as H he was living it up in a three million pound mansion - and ordering hits on his enemies.
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His cover was so secure that even the officers he controlled didn't know who he was - which is why Jo Davidson framed him.
Hastings, Kate and Steve were horrified that H had been under their nose the entire time - and was hiding his massive corruption under his own bungling.